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ATOM
The atom and its particles
Term | Definition |
---|---|
Atomic number | Number of protons in the nucleus |
Mass number | Number of protons plus neutrons in the nucleus |
Atom | The smallest particle of a chemical element that can exist |
Proton | A stable subatomic particle with a positive electric charge equal in magnitude to that of an electron |
Neutron | A subatomic particle of about the same mass as a proton but without an electric charge |
Nucleus | The positively charged central core of an atom, consisting of protons and neutrons and containing nearly all its mass |
Subatomic particles | Particles that are smaller than the atom. The three main subatomic particles that form an atom are protons, neutrons, and electrons |
Electron shell | A grouping of electrons surrounding the nucleus of an atom |
Isotope | Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei |
Ion | An electrically charged atom or group of atoms formed by the loss or gain of one or more electrons |